1. Field of the Invention
The present invention relates to a tire pressure detecting device and a tire monitor system both of which detect an internal pressure of a tire and transmit data of results of detection between a wheel and a vehicle body by radio.
2. Description of the Related Art
One of known tire pressure detecting devices comprises a transponder with a pressure sensor connected thereto. When receiving radio waves transmitted from a vehicle body, the tire pressure detecting device detects an internal pressure of a tire with the pressure sensor, sending data of the detection back to the vehicle body. For example, JP-A-2004-189034 discloses one of the above-noted tire pressure detecting devices.
The tire pressure detecting devices have recently come into wide use. However, lower cost and higher precision are required of the tire pressure detecting device for further widespread diffusion.